In the production process of semiconductor integrated circuit devices, after a great number of integrated circuits are formed on a wafer, a probe test is generally conducted as to each of these integrated circuits. This wafer is then cut, thereby forming semiconductor chips. Such semiconductor chips are contained and sealed in respective proper packages. Each of the packaged semiconductor integrated circuit devices is further subjected to a burn-in test. In order to give a quality certification to a semiconductor integrated circuit device, it is extremely important to not only inspect electrical properties of the semiconductor integrated circuit device by the burn-in test, but also inspect electrical properties of a semiconductor chip itself. Besides, in recent years, there has been developed a mounting method that uses a semiconductor chip itself as an integrated circuit device and directly mount the circuit device composed of the semiconductor chip on a printed circuit board. Therefore, there is a demand for guaranteeing the quality of the semiconductor chip itself.
It takes a long time to conduct inspection of the circuit device composed of the semiconductor chip, and inspection cost becomes considerably high because the semiconductor chip is minute, and its handling is inconvenient.
From such reasons, attention has been recently paid to a WLBI (wafer level burn-in) test in which the electrical properties of the circuit board composed of the semiconductor chip are inspected in the state of a wafer.
FIG. 13 is a cross-sectional view schematically illustrating the construction of an exemplary conventional wafer inspection apparatus for conducting the WLBI test as to a wafer on which a great number of integrated circuits have been formed.
This wafer inspection apparatus has a controller 85 having an input-output terminal part 86 in which a great number of input-output terminals 87 have been arranged. This controller 85 serves to perform temperature control of a wafer 1 for the purpose of conducting the inspection of the wafer 1 at a prescribed temperature, supply an electric power for conducting the inspection of the wafer 1, make input-output control of signals and detect output signals from the wafer 1 to judge the quality of integrated circuits on the wafer 1.
A disk-like circuit board 80 for inspection is provided below the controller 85. A leading terminal part 81, in which a great number of leading terminals 82 have been arranged in accordance with a pattern corresponding to a pattern of the input-output terminals 87 in the controller 85, is formed at a peripheral edge portion in one surface (upper surface in FIG. 13) of the circuit board 80 for inspection. An inspection electrode part (not illustrated), in which a great number of inspection electrodes (not illustrated) electrically connected to the respective leading terminals 81 through a circuit in the circuit board 80 for inspection have been arranged, is formed at a central portion of said one surface of the circuit board 80 for inspection. The circuit board 80 for inspection is arranged in a state held by a proper holding member in such a manner that the respective leading terminals 82 are opposed to the input-output terminals 87 of the controller 85.
A contact member 83 having a great number of contactors (not illustrated) brought into contact with electrodes (not illustrated) to be inspected of the integrated circuit in the wafer 1 as an object of the inspection is arranged on the inspection electrode part in said one surface of the circuit board 80 for inspection, and the each of the contactors of this contact member 83 are electrically connected to the respective inspection electrodes of the circuit board 80 for inspection.
A connector 84, in which a great number of connecting pins 84a capable of being elastically compressed in a lengthwise direction thereof, which are called “pogo pins”, have been arranged, is arranged between the leading terminal part 81 of the circuit board 80 for inspection and the input-output terminal part 86 of the controller 85 in a state that the connecting pins 84a have been pressed in the lengthwise direction against the respective input-output terminals 87 of the controller 85 by means of a proper pressing mechanism (not illustrated), and the leading terminals 82 of the circuit board 80 for inspection are electrically connected to the input-output terminals 87 of the controller 85 by this connector 84.
FIG. 14 is a cross-sectional view schematically illustrating the construction of another exemplary conventional wafer inspection apparatus for conducting the WLBI test as to a wafer on which a great number of integrated circuits have been formed. In this wafer inspection apparatus, a controller 95 having a surface (upper surface in FIG. 14) of an area greater than a circuit board 80 for inspection is provided, the circuit board 80 for inspection is arranged at a central portion of said one surface of the controller 95, and a contact member 83 having a great number of contactors (not illustrated) is arranged on an inspection electrode part (not illustrated) in the circuit board 80 for inspection.
An input-output terminal part 96, in which a great number of input-output terminals 97 have been arranged, is formed at a peripheral edge portion in said one surface of the controller 95, and a connector 90 composed of a flexible printed wiring board having a great number of connection terminals 91 and 92 arranged in accordance with patterns corresponding to patterns of the each of the leading terminals 82 and the input-output terminals 97 is arranged on the leading terminal part 81 of the circuit board 80 for inspection and the input-output terminal part 96 of the controller 95 in such a manner that the each of the connection terminals 91 and 92 are opposed to the respective leading terminals 82 and the input-output terminals 97. The connector 90 is fixed to the leading terminal part 81 of the circuit board 80 for inspection and the input-output terminal part 96 of the controller 95 with anisotropically conductive adhesives 93 and 94, respectively, and the connection terminals 91 and 92 of the connector 90 are electrically connected to the leading terminals 82 of the circuit board 80 for inspection and the input-output terminals 97 of the controller 95, respectively.
In the wafer inspection apparatus shown in FIG. 13 or FIG. 14, the wafer 1 as an object of the inspection is held by a wafer holder 88 combined with a heating plate, and the wafer holder 88 is pressed downward by proper means, whereby the contactors of the contact member 83 are brought into contact with respective electrodes to be inspected of all integrated circuits formed on the wafer 1, thereby achieving necessary electrical connection. After the wafer 1 is heated to a prescribed temperature by the wafer holder 88 and held for a long period of time in this state, necessary electrical inspection (burn-in test) as to the wafer 1 is performed.
On the other hand, in the probe test conducted on integrated circuits formed on a wafer, a method, in which a probe test is collectively performed on, for example, 16 or 32 integrated circuits among a great number of integrated circuits formed on a wafer, and the probe test is successively performed on other integrated circuits, is generally adopted.
In recent years, there has been a demand for collectively performing a probe test on, for example, 64 or 124 integrated circuits, or all integrated circuits among a great number of integrated circuits formed on a wafer for the purpose of improving inspection efficiency and reducing inspection cost.
FIG. 15 is a cross-sectional view schematically illustrating the construction of an exemplary conventional wafer inspection apparatus for conducting the probe test as to a great number of integrated circuits formed on a wafer.
A circuit board 80 for inspection in this wafer inspection apparatus has a leading terminal part 81, in which a great number of leading terminals 82 have been arranged correspondingly to input-output terminals 87 in a controller 85, on one surface (upper surface in FIG. 15) and an inspection electrode part (not illustrated), in which a great number of inspection electrodes (not illustrated) electrically connected to the respective leading terminals 82 by a circuit in the circuit board 80 for inspection have been arranged, on the other surface, and is held by a holding member 74.
On the inspection electrode part in the other surface of the circuit board 80 for inspection, is arranged a contact member 83 having a great number of contactors (not illustrated) brought into contact with electrodes (not illustrated) to be inspected of integrated circuits on a wafer 1 as an object of the inspection. The respective contactors of this contact member 83 are electrically connected to the respective inspection electrodes of the circuit board 80 for inspection.
A wafer tray 89 combined with a heating plate, on which the wafer 1 as the object of the inspection is mounted, is arranged under the contact member 83.
A circuit board 75 for connection is provided between the controller 85 and the circuit board 80 for inspection. The circuit board 75 for connection has one-side connecting electrode part 76, in which a great number of one-side connecting electrodes 77 have been arranged in accordance with a pattern corresponding to a pattern of the input-output terminals 87 in the controller 85, on one surface (upper surface in FIG. 15) thereof and the other-side connecting electrode part 78, in which a great number of other-side connecting electrodes 79 have been arranged in accordance with a pattern corresponding to a pattern of the leading terminals 82 in the circuit board 80 for inspection, on the other surface thereof. The circuit board 75 for connection is arranged in a state held by a holding member 74 in such a manner that the one-side connecting electrodes 77 are respectively opposed to the input-output terminals 87 of the controller 85, and the other-side connecting electrodes 79 are respectively opposed to the leading terminals 82 of the circuit board 80 for inspection.
A first connector 70, in which a great number of connecting pins 71 capable of being elastically compressed in a lengthwise direction thereof have been arranged, is arranged between the input-output terminal part 86 of the controller 85 and the one-side connecting electrode part 76 of the circuit board 75 for connection in a state that the connecting pins 71 have been pressed in the lengthwise direction by a proper pressing mechanism (not illustrated), and the input-output terminals 87 of the controller 85 are electrically connected to the one-side connecting electrodes 77 of the circuit board 75 for connection by this first connector 70.
A second connector 72, in which a great number of connecting pins 73 capable of being elastically compressed in a lengthwise direction thereof have been arranged, is arranged between the leading terminal part 81 of the circuit board 80 for inspection and the other-side connecting electrode part 78 of the circuit board 75 for connection in a state that the connecting pins 73 have been pressed in the lengthwise direction by the pressing mechanism, and the leading terminals 82 of the circuit board 80 for inspection are electrically connected to the other-side connecting electrodes 79 of the circuit board 75 for connection by this second connector 72.
In the wafer inspection apparatus shown in FIG. 15, the wafer 1 as the object of the inspection is mounted on the wafer tray 89, and the wafer tray 89 is moved upward by proper means, whereby the contactors of the contact member 83 are brought into contact with the respect electrodes to be inspected of a part of the integrated circuits formed on the wafer 1, thereby achieving necessary electrical connection. The wafer 1 is then heated to a prescribed temperature by the wafer tray 89 to perform necessary electrical inspection (probe test) as to the wafer 1 in this state.
The conventional wafer inspection apparatus shown in FIGS. 13 to 15 involve the following respective problems.
(1) In the wafer inspection apparatus shown in FIGS. 13 and 15, it is necessary to press the connecting pins under pressing force of about 0.8 N (about 0.08 kgw) per pin for the purpose of achieving stable electrical connection of the input-output terminals 87 of the controller 85 to the respective leading terminals 82 of the circuit board 80 for inspection. Accordingly, when the number of, for example, leading terminals 82 of the circuit board 80 for inspection is, for example, 5,000, pressing force of about 4,000 N is required as a whole. Therefore, the apparatus involve a problem that a pressing mechanism for applying such pressing force inevitably becomes large in size, and a large-scaled member that withstands great pressing force is also required for the holding member for the circuit board 80 for inspection, so that the whole wafer inspection apparatus becomes considerably large in size.
The apparatus also involve a problem that the service life of the circuit board 80 for inspection is shortened because the each of the leading terminals 82 of the circuit board 80 for inspection are pressed under great pressing force by the connecting pins, whereby the respective leading terminals 82 are easy to be damaged, and in turn, inspection cost is increased.
There is a limit to reduce a length of the connecting pins from the constraint of mechanism, and the connecting pins are required to have a length of about 3 cm in reality. Therefore, a clearance between the circuit board 80 for inspection and the controller 85 becomes considerably long. As a result, it is difficult to reduce the size of the wafer inspection apparatus in a height-wise direction. In this respect, the apparatus also involve a problem that the miniaturization of the wafer inspection apparatus as a whole cannot be contrived. In particular, there has recently been proposed a wafer inspection apparatus constructed by stacking a plurality of inspection units each composed of the components shown in, for example, FIG. 13 for the purpose of performing inspection as to a plurality of wafers in a small operating space in parallel. In such a wafer inspection apparatus, it is extremely important from the viewpoint of miniaturizing the apparatus to reduce the size of each inspection unit in a height-wise direction because the whole wafer inspection apparatus becomes considerably large when the size of each inspection unit in the height-wise direction is large.
Since the connecting pins require to have a considerably long length, a distance of a signal transmission system becomes considerably long, so that a problem that the apparatus are difficult to be applied to electrical inspection as to high functional integrated circuits of which high-speed processing is required arises.
(2) In the wafer inspection apparatus shown in FIG. 14, the leading terminals 82 of the circuit board 80 for inspection are electrically connected to the respective input-output terminals 97 of the controller 95 by the connector 90 composed of the flexible printed wiring board, so that it is difficult to arrange the leading terminal 82 at a high density. Accordingly, the apparatus involves a problem that it is difficult to collectively conduct inspection as to a great number of electrodes to be inspected because only about 2,000 leading terminals can be formed on the circuit board 80 for inspection.
Since electrical connection between the connecting terminals 91 of the connector 90 and the leading terminals 82 of the circuit board 80 for inspection and electrical connection between the connecting terminals 92 of the connector 90 and the input-output terminals 97 of the controller 95 are achieved by the anisotropically conductive adhesives 93 and 94, respectively, contact resistance becomes considerably high. Accordingly, a problem that good electrical properties cannot be achieved arises.